For several decades, a major focus of machining research has been the measurement and prediction of temperature. Here, the influence of the rate of heating on the flow stress, and the implications of this for finite-element modeling of high speed metal-cutting processes, will be discussed. First, for a range of chip thicknesses, a description will be given of some infrared microscopic measurements, performed at NIST, of the temperature field at the tool-chip interface during steady-state orthogonal machining of AISI 1045 steel. Next, some unsuccessful attempts to predict these thermal fields using commercial finite-element software will be discussed. Following this, results will be presented of some recent NIST research using a split-Hopkinson (Kolsky) bar with a rapid preheating capability. This work implies that, in AISI 1045 steel and related mild steels of interest in manufacturing, the thermal-softening effect during high-speed machining is significantly smaller than predicted by current constitutive response models. Finally, it will be shown that improved finite-element predictions of the maximum temperature on the tool-chip interface are obtained using the pulse-heated Kolsky bar data.
Conference Dates: May 4-5, 2004
Conference Location: Cluny, FR
Conference Title: 7th CIRP International Workshop on Modeling and Machining Operations
Pub Type: Conferences
material behavior, metal cutting, SHPB strain, strain rate, temperature